a) Field of the Invention
The present invention relates to a starter battery which provides a car or a motorcycle with the power needed to operate a starter motor, and more particularly to a vehicular starter battery management system.
b) Description of the Prior Art
A starter battery of a vehicle like a car or a motorcycle is a kind of secondary battery which can be recharged and discharged. The starter battery provides the power needed to operate a starter motor, allowing the starter motor to operate and activate an engine. When a vehicle engine is not operating, the starter battery will provide electricity to all kinds of vehicular electronic and electric equipment, such as a car lamp or a vehicle ECU (Electronic Control Unit). On the other hand, when the vehicle engine is running, the engine will drive a generator to operate, producing electricity for the starter battery and the abovementioned vehicular electronic and electric equipment.
The vehicular starter battery installed in a vehicle like a car or a motorcycle includes a power terminal set, an accumulator unit and a battery management unit. The power terminal set is used to connect with an electrical connector terminal of the vehicle, and the accumulator unit is formed by connecting plural lithium-iron-phosphate battery cores serially or parallel to accumulate the power. The power terminal set and the accumulator unit are coupled together by the battery management unit which is formed primarily by an electronic circuit. The battery management unit includes a charging circuit and a discharging circuit, the charging circuit and the discharging circuit are connected together parallel and are connected respectively with the power terminal set and the accumulator unit. The power generated by the generator recharges the accumulator unit through the charging circuit, and the power of the accumulator unit discharges to an exterior of the vehicular starter battery through the discharging circuit, so as to supply electricity to the vehicular electronic and electric equipment. By changing the on/off states of the charging circuit and the discharging circuit, the battery management unit manages the charging and discharging of the accumulator unit, preventing the accumulator unit from being recharged excessively or discharged excessively.
When the vehicle engine is not running, the starter battery will provide the electricity to all kinds of vehicular electronic and electric equipment, such as a car lamp or an ECU. On the other hand, if the vehicle engine has not been activated or operating for a long time, the power accumulated in the accumulator unit will be consumed gradually and will not be supplemented. If the electricity stored in the lithium-iron-phosphate battery cores reaches to a lower safety limit, then the activity of the lithium-iron-phosphate battery cores will be affected, which reduces the lifetime of use and the effective storage capacity of the lithium-iron-phosphate battery cores. In addition, it will not be able to provide the vehicle with the power needed to operate the starter motor to activate the engine, and the vehicle engine will not be activated.